Oven having an enclosed heat exchange zone

ABSTRACT

An oven has an enclosed heat exchange zone for use with biomass fuel. The oven has a body which is able to be placed on the ground. The body has a combustion cabinet and an auxiliary equipment cabinet. The combustion cabinet has a burner received therein. The burner has a fire grate, a side plate, a blowing space, and a hearth. A heat exchange zone is defined by the surrounding tubular inner wall; a side heating zone being defined by a tubular inner and a tubular outer walls. A chimney is formed on the tubular outer wall in communication with an upper portion of the side heating zone. An opening is defined in the top of the combustion cabinet right above the tubular inner wall.

CROSS-REFERENCE TO RELATED APPLICATIONS

Not Applicable

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable

INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC

Not Applicable

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to an oven for use with biomass fuel, and more particularly, to an oven using granule made by smashed and then briquetted straw, bits of wood, or crop stalks and having an enclosed heat exchange zone which is able to much increase a use ratio of heat energy.

2. Description of Related Art

Biomass fuel is granule made by smashed and then briquetted straw, bits of wood, or crop stalks. As a new energy solution, biomass fuel has wider and wider been used because it is hygienic, environmental, high efficient, and economic.

A type traditional biomass oven is disclosed in a Chinese utility model paten “A Heat Storage Oven” numbered CN201903090U. As shown in FIG. 5, the oven has a burning chamber (not shown), in which biomass fuel burns. A hearth 91 is provided right above the burning chamber. The hearth 91 has a top opening 92. A top kitchen range 96 is provided around the top opening 92. A zone above the top kitchen range 96 and right beyond the top opening 92 is a heat exchange zone 93. A heating or cooking appliance such as a pot containing food or water is able to be put above the heat exchange zone 93 on the top kitchen range 96. Or food needs to be heat is able to be placed above the heat exchange zone 93 directly. Flames generated in the burning chamber goes out of the top opening 92 through the hearth 91 and heats the food or cooking appliance at the heat exchange zone 93. A supplemental air supply chamber 94 may be provided around an outer surface of top portion of the hearth. A plurality of air supply vents 95 are defined in a wall of the hearth 91 in communication with the supplemental air supply chamber 94. An air pipe (not shown) is provided in communication with an inlet of the supplemental air supply chamber 94 and supplies air for the hearth 91 through the supplemental air supply chamber 94 and the air supply vents 95. The supplemental air supply chamber 94 is able to make the unburned gas in the hearth 91 burn completely thus increasing an efficiency of combustion. An air pollution caused by the unburned gas is also able to be decreased.

However, this traditional oven still has a problem of energy waste because an open heat exchange zone 93 will cause a heavy loss of heat of flames into the environment.

BRIEF SUMMARY OF THE INVENTION

The main object of the invention is to provide an oven having an enclosed heat exchange zone which is able to decrease waste of heat energy and has a higher energy use ratio than the traditional biomass oven.

In order to accomplish the above objects, the present invention provides an oven having an enclosed heat exchange zone for use with biomass fuel. The oven has a body which is able to be placed on the ground. The body has a combustion cabinet and an auxiliary equipment cabinet. The combustion cabinet has a burner received therein. The burner has a fire grate, a side plate extending upward from a peripheral of the fire grate, a blowing space beneath the fire gate, and a hearth defined by the fire grate and the surrounding side plate. A plurality of air vents are defined in the fire grate. A heating portion is above the burner. The heating portion has a tubular inner wall and a tubular outer wall. A heat exchange zone is defined by the surrounding tubular inner wall; a side heating zone being defined by the tubular inner and the tubular outer walls. A plurality of flame vents are defined in a lower portion of the tubular inner wall near the burner. A chimney is formed on the tubular outer wall in communication with an upper portion of the side heating zone. An opening is defined in the top of the combustion cabinet right above the tubular inner wall. The auxiliary equipment cabinet has a fuel supply mechanism and an electrical equipment received therein. The fuel supply mechanism has a hopper, a fuel tube having one end in communication with the hopper and a free end extending into the hearth, and a rotary vane feeder rotatably received in the fuel tube. The electrical equipment has a feeding motor driving the rotary vane feeder, an air blower for supplying air to the blowing space, a power supply, and a switch.

The bonfire oven of the invention has following beneficial effects. In a whole process of heat exchange, the heat exchange zone is enclosed. Flames are able to heat both directly in the heat exchange zone, and complementarily in the side heating zone. Much less heat will lose as the open heat exchange zone in the traditional oven. Therefore, the heat energy is high efficiently used in the oven of the invention.

These and other objectives, features, and advantages of the present invention will become apparent from the following detailed description, the accompanying drawings, and the appended claims.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a schematic perspective view of the preferred embodiment of an oven of the invention.

FIG. 2 is atop plan view of the oven shown in FIG. 1.

FIG. 3 is a cross-sectional plan view along the direction A-A shown in FIG. 2.

FIG. 4 is a circuit diagram of an electrical equipment of the oven shown in FIG. 1. And,

FIG. 5 is a cross-sectional schematic plan view of a traditional biomass fuel oven.

DETAILED DESCRIPTION OF THE INVENTION

Shown in FIG. 1 is the preferred embodiment of an oven having an enclosed heat exchange zone of the invention. The oven has a body 1 which is able to be placed on the ground. The body 1 has a combustion cabinet 10 and an auxiliary equipment cabinet 20.

With reference to FIGS. 2 and 3, the combustion cabinet 10 has a bottom 11 which is able to be placed on the ground levelly, a side 12 extending upward from a peripheral of the bottom 11, and a top 13 in communication with an upper peripheral of the side 12 and opposite to the bottom 11. An openable door 121 is provided in the side 12.

The combustion cabinet 10 has a burner 30 received therein. The burner 30 has a fire grate 31, a side plate 32 extending upward from a peripheral of the fire grate 31, and a blowing space 33 beneath the fire grate 31. A hearth 34 is defined by the fire grate 31 and the surrounding side plate 32. A plurality of air vents 311 are defined in the fire grate 31. An ignition bar window 312 may be defined in the fire grate 31, too. An ignition bar 61 may be installed in the blowing space 33 and exposed to the hearth 34 through the ignition bar window 312.

A heating portion 40 is above the burner 30. The heating portion 40 has a tubular inner wall 41 and a tubular outer wall 42. A heat exchange zone 43 is defined by the surrounding tubular inner wall 41. A side heating zone 44 is defined by the tubular inner and the tubular outer walls 41, 42. A plurality of flame vents 411 are defined in a lower portion of the tubular inner wall 41 near the burner 30. The plurality of flame vents 411 may be in a circular row having equal distance with each other, as shown in this preferred embodiment. A chimney 45 is formed on the tubular outer wall 42 in communication with an upper portion of the side heating zone 44. The chimney 45 goes out of the body 1 through the auxiliary equipment cabinet 20. An opening 131 is defined in the top 13 of the combustion cabinet 10 right above the tubular inner wall 41. An oven lid (not shown) may be provided covering on the opening 131. A circular stage 412 may be defined in an inner surface of the tubular inner wall 41 above the flame vents 411. The circular stage 412 is suitable for supporting a pot (not shown).

The auxiliary equipment cabinet 20 has a fuel supply mechanism 50 and an electrical equipment 60 received therein. The fuel supply mechanism 50 has a hopper 51, a fuel tube 52 having one end in communication with the hopper 51 and a free end extending into the hearth 34, and a rotary vane feeder 53 rotatably received in the fuel tube 52. The electrical equipment 60, as shown in FIG. 4, has the ignition bar 61, a feeding motor 62 driving the rotary vane feeder 53, an air blower 63 being able to supply air to the blowing space 33, a power supply 64, a switch 65 and a power light 66. The power supply 64 may be an independent alternating current/direct current power supply 641, having or having not a storage battery 642 in parallel as auxiliary. Either the alternating current/direct current power supply 641 or the storage battery 642 is able to supply power independently. The switch 65 is installed on the auxiliary equipment cabinet 20 and able to control the power supply of whole circuit. The power light 66 is also installed on the auxiliary equipment cabinet 20 near the switch 65 and used to indict status of power supply.

Fuel 70 is biomass fuel granule made by smashed and then briquetted straw, bits of wood, or crop stalks.

In use, a user is able to first place smooth the body 1 of the oven on the ground where is desirable and then load fuel 70 into the hopper 51. The user is able to either put water or food directly into the heat exchange zone 43 and then place the oven lid on the opening 131 of the top 13, or place a pot having a shape matching the tubular inner wall 41 onto the stage 412 within the heat exchange zone 43. When the user turns on then switch 65, the power light 66 turns up, which means the electrical circuit is closed and the oven starts to work. The feeding motor 62 starts to rotate, driving the rotary vane feeder 53 to send the fuel 70 into the burner 30. Biomass fuel granule falls onto the fire grate 31 under the gravity. At this time, the ignition bar 61 is electrified and becomes red-hot and will ignite the fuel 70 on the fire grate 31 through the ignition bar window 312. At this time too, the air blower 63 start to supply air to the blowing space 33. Air enters the hearth 34 through the air vents 311 in the fire grate 31 and provides oxygen for combustion of the fuel 70. Methane gas is created in a process of burning of the fuel 70. With air flow produced by the air blower 63, the methane gas burns into flames. In whichever situation, the food being directly put in the heat exchange zone 43 and then the oven lid being placed one the opening 131, or the pot being put on the stage 412 within the heat exchange zone 43, the heat exchange zone 43 is an enclosed space. The only passageway of flames is through the flame vents 411, the side heating space 44 and then the chimney 45. After the fuel 70 is able to sustainably burn, the circuit may turn of the ignition bar 61 to save electrical power. The user is able to process the food by opening the oven lid or a pot lid at any time.

When the user needs to stop the burning, he is able to turn off the switch 65, and the power light 66 goes out, the feeding motor 62 stops to rotate, and the air blower 63 ceases. As there is no new supply of fuel 70, the fuel in the hearth 34 will burn up in a very short time period. The user then is able to open the door 121 and collect ash in the blowing space 33. Outer region of the fire grate 31 may be oblique upward in a certain degree in order to form a central depression. The central depression is useful to gather fuel together to avoid black smoke caused by insufficient burning of the outer region fuel 70.

From above description, it is seen that the objects of the present invention have been fully and effectively accomplished. Embodiment of the invention has been shown and described for the purposes of illustrating the functional and structural principles of the present invention and is subject to change without departure from the invention's principles. Therefore, this invention includes all modifications encompassed within the spirit and scope of the following claims. 

1. An oven having an enclosed heat exchange zone for use with biomass fuel comprising: a body which is able to be placed on the ground, said body having a combustion cabinet and an auxiliary equipment cabinet, said combustion cabinet having a burner received therein, said burner having a fire grate, a side plate extending upward from a peripheral of said fire grate, a blowing space beneath said fire grate, and a hearth defined by said fire grate and said surrounding side plate, a plurality of air vents being defined in said fire grate, a heating portion being above said burner, said heating portion having a tubular inner wall and a tubular outer wall, a heat exchange zone being defined by said surrounding tubular inner wall, a side heating zone being defined by said tubular inner and said tubular outer walls, a plurality of flame vents being defined in a lower portion of said tubular inner wall near said burner, a chimney being formed on said tubular outer wall in communication with an upper portion of said side heating zone, an opening being defined in said top of said combustion cabinet right above said tubular inner wall, said auxiliary equipment cabinet having a fuel supply mechanism and an electrical equipment received therein, said fuel supply mechanism having a hopper, a fuel tube having one end in communication with said hopper and a free end extending into said hearth, and a rotary vane feeder rotatably received in said fuel tube, said electrical equipment having a feeding motor driving said rotary vane feeder, an air blower for supplying air to said blowing space, a power supply, and a switch.
 2. The oven as claimed in claim 1, wherein a circular stage is defined in an inner surface of said tubular inner wall above said flame vents.
 3. The oven as claimed in claim 1, wherein an ignition bar window is defined in said fire gate, and said electrical equipment further has an ignition bar being installed in said blowing space, said ignition bar being exposed to said hearth through said ignition bar window and powered by said power supply.
 4. The oven as claimed in claim 2, wherein an ignition bar window is defined in said fire grate, and said electrical equipment farther has an ignition bar being installed in said blowing space, said ignition bar being exposed to said hearth through said ignition bar window and powered by said power supply. 